Watts to lux calculator

Electric power in watts (W) to illuminance in lux (lx) calculator and how to calculate.

Enter the power in watts, luminous efficacy in lumens per watt, surface area in square feet / meters or spherical radius in feet / meters and press the Calculate button to get the illuminance in lux:

Enter power in watts:  
W
Select light source
Or enter luminous efficacy in lumens per watt:
lm/W
Enter surface area:  
Or enter spherical radius:  
   
 
   
Illuminance result in lux:  
lx

Lux to watts calculator ►

* the predefined luminous efficacy values are typical / average values.

Watts to lux calculation formula

Watts to lux calculation with area in square feet

The illuminance Ev in lux (lx) is equal to 10.76391 times the power P in watts (W), times the luminous efficacy η in lumens per watt (lm/W) divided by the surface area A in square feet (ft2):

Ev(lx) = 10.76391 × P(W) × η(lm/W) / A(ft2)

Watts to lux calculation with area in square meters

The illuminance Ev in lux (lx) is equal to the power P in watts (W), times the luminous efficacy η in lumens per watt (lm/W) divided by the surface area A in square meters (m2):

Ev(lx) = P(W) × η(lm/W) / A(m2)

 

Watts to lux calculation ►

 

See also

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